Heat and Energy Efficiency Technical Suitability Assessment (HEETSA) - Scoping Consultation

We consulted from 6 June to 29 August 2025 on initial proposals for the scope of a Heat & Energy Efficiency Technical Suitability Assessment (HEETSA). We proposed that HEETSA would be an optional step beyond an Energy Performance Certificate (EPC) assessment.

We proposed that HEETSA would provide a more detailed and technically robust buildings’ assessment than the standardised, modelled assumptions of the EPC, and would take account of factors such as building condition, location, climate, ventilation (and the risk of condensation, dampness and mould) and occupant behaviour.

We set out how HEETSA could complement the existing EPC assessment process, and the role it could play in supporting any legislation on clean heating and minimum energy efficiency standards - Delivering net zero for Scotland's buildings - Heat in Buildings Bill: consultation - gov.scot; Draft Energy Efficiency (Domestic Private Rented Property) (Scotland) Regulations: consultation - gov.scot; Social housing net zero standard: consultation - gov.scot; Heat in buildings: future plans - gov.scot. HEETSA would provide more detailed recommendations on which measures were technically suitable to meet such standards, and on where exemptions could be necessary to prevent risks such as dampness or mould, if unsuitable measures were installed.

We therefore saw HEETSA as a potentially important safeguard for consumers planning to take action to improve the performance of their building, where they need additional information on which energy efficiency and clean heating measures are suitable for their building and which are not. This would be particularly important in safeguarding more complex and difficult-to-decarbonise buildings such as tenements, traditional and protected buildings.

We proposed that HEETSA should build upon existing retrofit assessment methodologies already in use and being developed in the market, and filling any gaps. We proposed that, as with the EPC system, the Scottish Government would approve the methodologies, professional standards (skills / qualifications) and specify the format for HEETSA certification and reporting the results of the assessment.

We issued a written consultation paper which asked 13 questions covering the following main themes:

• value and purpose of a HEETSA
• scope and methodology of a HEETSA
• delivery and accreditation
• skills and capacity
• data and integration
• legal and regulatory framework

We also hosted three consultation workshops in July and August 2025, to cover the themes in the consultation paper.

We received 88 responses to the consultation, with 70 received from organisations and 18 from individuals.

Overall, a majority (79%) of respondents to the headline question agreed that the Scottish Government should develop a HEETSA framework for the retrofit of buildings. HEETSA should build on existing assessment and investigative methodologies and improve on shortcomings (i.e. address gaps in the market) rather than create something new. Additional training would be needed in some circumstances to ensure that assessors had the skills needed to address more complex buildings. Respondents supported a regulated delivery model to ensure that HEETSA assessors were independent, and that HEETSA results should be presented in a standardised form.

Key findings across the main themes were:

Value and purpose of a HEETSA

There was general support for the development of a HEETSA, with reasons given including:

• quality and accountability in retrofit advice
• standardised and holistic assessment approach
• empowering consumers through better advice
• supporting public policy and resource efficiency
• upskilling and growing the retrofit workforce

Some concern was expressed about the affordability of HEETSA and whether it could be ready by 2027.

In response to a question on any circumstances in which a HEETSA should be required, respondents highlighted the following:

• specific situations – the most common suggested triggers for a HEETSA were either to access public funding for retrofit, or to demonstrate regulatory compliance / justify exemption, in particular linked to the proposed private rented sector minimum energy efficiency standard (PRS MEES).
• specific building types – HEETSA should be required for retrofit of specific building types including hard-to-treat, historic, traditional or listed buildings, and communal or tenement buildings.
• specific building works – the requirement for a HEETSA should depend on the type of retrofit works, in particular before installation of a clean heating system or when significant building refurbishment takes place.

Scope and methodology of a HEETSA

78% of respondents thought that HEETSA should cover retrofit assessment, whilst additionally, respondents thought that HEETSA should cover retrofit design (66%), occupancy-related factors (60%) and retrofit specification (50%). Some respondents felt that HEETSA should cover all of the retrofit lifecycle stages whilst a similar number suggested that HEETSA should focus on the assessment phase only.

Respondents recommended a diverse range of existing methodologies and standards to assess different aspects of retrofit. Gaps were identified around making greater use of real-world performance data, including post-occupancy evaluation, to verify the impact of improvements rather than relying on assumed performance. This would enable HEETSA assessors to draw on corroborated evidence when determining suitable measures, which is particularly important for hard-to-treat buildings such as tenements where modelled assumptions can be unreliable.

Respondents also emphasised the need for clearer guidance to broaden what qualifies as acceptable ‘documentary evidence’ within EPC assessments, noting that current practice often defaults to worst-case assumptions. Improved guidance, implemented through schemes, would support more informed and consistent decision-making. Alongside this, further work is needed to strengthen evaluation methods tailored to traditional and hard-to-treat buildings and to improve guidance on selecting clean heating systems for specific building types and different environments. These gaps should be addressed through the Scottish Government leading and funding the development of improved methodologies, and by consulting and collaborating with professional bodies and those delivering or researching retrofit. Ultimately, this could allow HEETSA outputs to act as qualified documentary evidence that future EPC assessments would be required to adopt.

Some respondents raised concerns about potential duplication with PAS 2035. To address this, it is important to clarify that HEETSA is intended to complement, rather than replicate, established retrofit processes. Within PAS 2035, the Retrofit Assessor collects building data, which is then used by a Retrofit Coordinator, who typically does not visit the property, to develop the retrofit plan. A HEETSA assessment, by contrast, provides a more detailed, site-specific evaluation based on real world evidence, enabling the assessor to identify both the most suitable improvement measures and any that may be detrimental to the building. The data gathering approach set out in BS 40104 can support both frameworks: for example, the same building level assessment for a tenement block could either form the final HEETSA output or feed into a PAS 2035 process where delivery is subsequently managed. HEETSA should therefore be seen as part of the wider retrofit landscape, providing enhanced diagnostic detail where needed and operating alongside PAS 2035 rather than in competition with it.

Delivery and accreditation

Most respondents (78%) supported some form of regulated structure in which HEETSA assessments are undertaken. The majority recommended that the Scottish Government should accredit organisations who in turn accredit HEETSA assessors.

The majority of respondents (86%) also thought that HEETSA assessors should be independent – to protect consumers from the installation of unsuitable retrofit measures by ensuring that assessment is carried out in a robust and unbiased manner.

Skills and capacity

Respondents suggested a range of existing skills and qualifications that could support HEETSA, with recognition that there is an existing pool of potential HEETSA assessors. Skillsets necessary to carry out the role of a HEETSA assessor would depend on the building type / situation requiring assessment and hence a modular approach could be adopted to upskill existing assessors depending on the building being assessed.

There was little appetite for the creation of an entirely new qualification, or discipline, to deliver HEETSA. In some cases, the skills could exist within an individual assessor; in others, multiple specialists might be needed, depending on the complexity of the building or project.

Data and integration

84% of respondents agreed that a HEETSA should result in a standardised certificate or report. The key benefits highlighted included the consistency of assessments and data collected, and the comparability of information between properties. 82% of respondents supported the storing of non-personal data gathered through a HEETSA within a ‘building logbook’ or ‘green building passport’.

Respondents recommended that a HEETSA report or certificate should provide property details such as current condition and past interventions; technical findings on suitable measures, show the benefits of alternative retrofit options and any risks and mitigations (e.g. related to mould and condensation) to enable informed decision-making based on carbon savings, installation and running costs. Information on the building’s performance against requirements and standards should also be presented.

Legal and regulatory framework

Most respondents (79%) agreed that it is necessary to develop a legal basis for HEETSA. This would safeguard consumers by ensuring accountability of HEETSA assessors and ensure delivery of a consistent, quality service. This would help improve market confidence and uptake of HEETSA. Care would be needed when developing any legal framework to avoid overlap and duplication with existing regulations and potentially a phased introduction.

Any legal framework for HEETSA would need to integrate with other proposed regulations such as PRS MEES and with the existing legal requirements for the EPC. 75% of respondents thought that HEETSA outputs should feed into the EPC, to help improve its accuracy. Others were, however, concerned to ensure that a clear separation was maintained between the EPC and HEETSA – particularly if introducing varying levels of accuracy could undermine the EPC’s role as a consistent, standardised comparative tool. There was also concern that linking HEETSA to EPCs might incentivise HEETSA assessors to prioritise measures that improve EPC ratings, rather than those best suited to the building.

We welcome the contribution of all stakeholders to the HEETSA consultation. We have reflected upon the consultation responses and can now confirm the Scottish Government’s intention to develop HEETSA further during the next Parliament. We will consult again in detail on our final proposed approach, and propose to do this in autumn-winter 2026-27.

In parallel we will begin work to commission the development of new methodologies to address the gaps identified by consultation respondents, and to review the skills and qualifications requirements for retrofit assessors. This will build upon the findings of the ongoing technical discovery project to scope the methodological and skills requirements of HEETSA, which is due to conclude later in spring 2026.

We will set out a final timeline for development and delivery of HEETSA in our next consultation.